Meteor Activity Outlook for August 28-September 3, 2010

The Meteor Activity Outlook is a weekly summary of expected meteor activity written by Robert Lunsford, Operations Manager of the American Meteor Society and contributor to this blog. The original unedited version of this week’s Meteor Activity Outlook can be found at the American Meteor Society’s site.

September offers longer nights in the northern hemisphere that tend to be less hazy than those experienced in mid-summer. In the sky, no major showers are visible from either hemisphere but the northern hemisphere enjoys the advantage of higher sporadic rates. Most of the shower activity this month is produced from the Perseus-Aurigid complex active this time of year. These showers rarely produce more than five meteors per hour but still manage to produce most of the shower activity seen this month. Unfortunately the Perseus-Aurigid complex lies too low in the northern sky for southern hemisphere observers to view very well. Video studies have shown that the Southern Taurids are visible as early as September 7th therefore after this date the Antihelion radiant will no longer be listed until the Taurid showers end in December. The Antihelion meteors are still active but their radiant is superimposed upon that of the more numerous Taurids, therefore it is impossible to properly separate these meteors. Observers in the southern hemisphere suffer from some of their lowest rates of the year this month. The Southern Taurid radiant is not too badly placed so observers south can expect to see a little of this activity this month.

During this period the moon reaches its last quarter phase on Wednesday September 1st. At this time the moon will be located ninety degrees west of the sun and will rise near 0100 local daylight time (LDT) for locations in the mid-northern latitudes of the northern hemisphere. This weekend the waning gibbous moon will rise during the late evening hours and remain in the sky the remainder of the night. Meteor observations are difficult under such circumstances unless your sky is transparent. The estimated total hourly rates for evening observers this week is ~3 from the northern hemisphere and ~2 from the southern hemisphere. For morning observers the estimated total hourly rates should be ~12 from the northern hemisphere and ~8 as seen from the southern hemisphere. The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity. During this period, moonlight reduces activity seen during the morning hours.

The radiant positions and rates listed below are exact for Saturday night/Sunday morning August 28/29. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately five sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near two per hour. As seen from the mid-southern hemisphere (45S), morning rates would be near fourteen per hour as seen from rural observing sites and three per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Morning rates are slightly reduced due to moonlight.

The following showers are expected to be active this week:

August Draconids (AUD)

The last few remnants from the August Draconids (AUD) may be seen this weekend. The radiant is currently located at 18:44 (281) +63. This position lies in southern Draco, ten degrees east of the second magnitude star Eltanin (Gamma Draconis). With an entry velocity of 23 km/sec. most of these meteors will appear to move slowly. The radiant is best placed near 2200 Local Daylight Time (10pm LDT) when it lies highest in the sky. Due to its high northern declination this shower is not well seen from the southern hemisphere.

Antihelions (ANT)

The wide Antihelion (ANT) radiant is now centered at 23:12 (348) -03. This area of the sky lies in western Pisces, three degrees north of the fourth magnitude star Phi Aquarii. This radiant is best placed near 0200 LDT when it lies on the meridian and is located highest in the sky. Due to the large size of this radiant, any meteor radiating from eastern Aquarius, southern Pegasus, western Pisces, or western Cetus could be a candidate for this shower. Rates at this time should be ~2 per hour no matter your location. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of medium-slow speed.

Alpha Aurigids (AUR)

The Alpha Aurigids (AUR) is the first radiant of the Perseus-Aurigid complex to become active. Maximum occurs on September 1, so rates this weekend will be very low. Even at maximum with a last quarter moon in the sky, rates will most likely not exceed one shower member per hour. The radiant position at maximum is 06:04 (091) +36. This position lies in eastern Auriga only one degree southeast of the third magnitude star Theta Aurigae. This is different than the old position which was close to Capella (Alpha Aurigae). Video results from the 2007 outburst of this shower showed that a majority of the activity came from the radiant near Theta Aurigae. The radiant is best placed near 0500 LDT, when it lies highest in a dark sky. With an entry velocity of 67 km/sec., most activity from this radiant would be swift. Activity can be seen, if it occurs, from the southern tropic regions during the last few hours before dawn.

The list below presents a condensed version of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning.

Shower Name                RA     DEC   Vel     Rates
                                        km/s   NH    SH
AUG August Draconids     18h 44m  +63    23    <1    <1
ANT Antihelions          23h 12m  -03    30     2     3
AUR Alpha Aurigids       06h 04m  +36    67     1    <1

RA - Right Ascension
DEC - Declination
Vel - Velocity relative to Earth (in km per sec)
Rates - Rate of visible meteors per hour from a
        dark site
NH - Northern Hemisphere
SH - Southern Hemisphere

August 23/24 to 29/30 Meteors

Even though there are no major showers currently active, meteor rates are still elevated as the background ‘Spoadic’ rate is near its annual peak.

Here in Tucson, the monsoon has taken a break after a rather active stretch. Though we are a little above our average rainfall level, the storms have been rather boring this year.

The nights should be clear for the next few days until the wind swings out of the southeast again and the monsoon moisture returns.

Obs  Date(UT)      Time    TOT SPO ANT PER AUD AUR
SAL3 2010-08-30   07h 26m   21  18  2   -   1   0
ALLS 2010-08-30   06h 52m   17  15  2   -   -   2
SAL3 2010-08-29   08h 15m   27  22  2   -   2   1
SAL3 2010-08-28   04h 47m   13  11  1   -   1   -
SAL3 2010-08-27   01h 11m   3   2   0   -   1   -
SAL3 2010-08-26   00h 00m   Bad weather
SAL3 2010-08-25   00h 00m   Bad weather
SAL3 2010-08-24   04h 12m   13  9   2   1   1   -

SAL3 - SALSA3 camera in Tucson (Carl Hergenrother)
ALLS - Near all-sky camera in Tucson (Carl Hergenrother)
VIST - Visual observations from Tucson (Carl Hergenrother)
SDG - Camera in San Diego operated by Bob Lunsford
Time - Total amount of time each camera looked for meteors
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
PER - Perseids
AUD - August Draconids
AUR - Aurigids

Meteor Activity Outlook for August 21-27, 2010

The Meteor Activity Outlook is a weekly summary of expected meteor activity written by Robert Lunsford, Operations Manager of the American Meteor Society and contributor to this blog. The original unedited version of this week’s Meteor Activity Outlook can be found at the American Meteor Society’s site.

Meteor activity kicks into high gear in August as seen from the northern hemisphere. The main reason for this activity surge is the Perseid shower that peaks on August 13. This shower is active most of the month and remains above the level of the sporadic background for a week centered on August 13. The sporadic activity is also increasing as seen from the northern hemisphere and is now nearly double the rates from just three months ago. As seen from south of the equator, meteor rates are still decent but falling rapidly. The sporadic rates seen at the beginning of the month will be twice as high as those seen during the last days of the month. The Perseid radiant does not rise high into the sky as seen in the southern hemisphere so rates from this shower are greatly reduced when compared to the northern hemisphere.

During this period the moon reaches its full quarter phase on Tuesday August 24th. At this time the moon will be located opposite the sun and will be in the sky all night long. This weekend the waxing gibbous moon will set near the start of morning twilight, depending on your latitude. The further north one is located, the earlier the moon will set, allowing more time to observe under dark skies. The estimated total hourly rates for evening observers this week is ~2 no matter your location. For morning observers the estimated total hourly rates should be ~8 from the northern hemisphere and ~6 as seen from the southern hemisphere. The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity. During this period, moonlight reduces activity seen during the morning hours.

The radiant positions and rates listed below are exact for Saturday night/Sunday morning August 21/22. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately five sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near two per hour. As seen from the mid-southern hemisphere (45S), morning rates would be near fourteen per hour as seen from rural observing sites and three per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Morning rates are slightly reduced due to moonlight.

The list below presents a condensed version of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning.

The detailed descriptions will be continued next week when the moonlight is not
as intense.

Shower Name                RA     DEC   Vel     Rates
                                        km/s   NH    SH
AUG August Draconids     18h 28m  +63    23    <1    <1
ANT Antihelions          22h 48m  -06    30     2     3
SDA Delta Aquariids      00h 01m  -10    42    <1    <1
PER Perseids             04h 04m  +60    61     1    <1

RA - Right Ascension
DEC - Declination
Vel - Velocity relative to Earth (in km per sec)
Rates - Rate of visible meteors per hour from a
        dark site
NH - Northern Hemisphere
SH - Southern Hemisphere

August 19/20 to 22/23 Meteors

Nightly meteor rates have been all over the place the past 4 nights. This has nothing to do with the actual rate of meteors and everything to do with the variable clouds plaguing Tucson every night. The monsoon is still in full force even if it never really rains here in town.

Even though we are a week and a half past the Perseid maximum, my cameras are still picking up a handful of  these meteors nearly every night.

I don’t turn on my near all-sky camera every night. The reason is I’m not comfortable operating it in the rain due to some of my “not exactly all-weather” extension cords. So if it’s raining or threatening to rain that night, I leave it off.

Obs  Date(UT)      Time    TOT SPO ANT PER SDA AUD
SAL3 2010-08-23   05h 31m   25  17  3   4   1   0
ALLS 2010-08-23   08h 35m   6   4   0   2   0   -
SAL3 2010-08-22   04h 10m   17  15  2   0   0   0
ALLS 2010-08-22   00h 00m   Not in Operation
SAL3 2010-08-21   01h 23m   2   1   1   0   0   0
ALLS 2010-08-21   00h 0mm   Not in Operation
SAL3 2010-08-20   05h 15m   16  10  1   3   2   0
ALLS 2010-08-20   09h 22m   7   4   0   2   1   0

SAL3 - SALSA3 camera in Tucson (Carl Hergenrother)
ALLS - Near all-sky camera in Tucson (Carl Hergenrother)
VIST - Visual observations from Tucson (Carl Hergenrother)
SDG - Camera in San Diego operated by Bob Lunsford
Time - Total amount of time each camera looked for meteors
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
PER - Perseids
SDA - Southern Delta Aquariids
AUD - August Draconids

August 18/19 Meteors

Another clear night… The Moon is starting to be a problem in the evening hours. For the rest of the week the Moon will set before the prime meteor watching hours in the early morning.

We are near the peak time of the Kappa Cygnids. This shower produces some of the most notable meteors, often ending with a bright flash. Last night didn’t produce any. Maybe we’ll see more tonight.

Obs  Date(UT)      Time    TOT SPO ANT PER SDA ERI KCG AUD
SAL3 2010-08-19   08h 11m   32  20  4   4   0   2   0   2
ALLS 2010-08-19   07h 35m   10  4   0   5   0   1   0   0

SAL3 - SALSA3 camera in Tucson (Carl Hergenrother)
ALLS - Near all-sky camera in Tucson (Carl Hergenrother)
VIST - Visual observations from Tucson (Carl Hergenrother)
SDG - Camera in San Diego operated by Bob Lunsford
Time - Total amount of time each camera looked for meteors
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
PER - Perseids
SDA - Southern Delta Aquariids
ERI - Eta Eridanids
KCG - Kappa Cygnids
AUD - August Draconids

August 15/16 to 17/18 Meteors

After 3 nights of mostly clouds, last night was clear enough to allow some good video meteor watching. Perseids rates are done big time now that we are a few days past maximum. None of the other active showers appear to be producing much.

Obs  Date(UT)      Time    TOT SPO ANT PER SDA ERI KCG AUD
SAL3 2010-08-18   06h 07m   26  17  3   5   0   0   1   0
SAL3 2010-08-17   00h 19m   1   0   0   1   0   0   0   0
SAL3 2010-08-16   00h 00m   Clouds/Rain all night
SAL3 2010-08-15   02h 30m   3   2   0   1   0   0   0   0

SAL3 - SALSA3 camera in Tucson (Carl Hergenrother)
ALLS - Near all-sky camera in Tucson (Carl Hergenrother)
VIST - Visual observations from Tucson (Carl Hergenrother)
SDG - Camera in San Diego operated by Bob Lunsford
Time - Total amount of time each camera looked for meteors
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
PER - Perseids
SDA - Southern Delta Aquariids
BPE - Beta Perseids
ERI - Eta Eridanids
KCG - Kappa Cygnids
AUD - August Draconids

The rains have returned

Not much to report here in Tucson the past 2 nights as the monsoon rains have returned. Until the weather clears enough to allow meteor observations, the daily reports will be intermittent.

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